This invention relates to electrosurgery and more particularly to electrosurgical electrodes (e.g., probes or blades) for use in performing electrosurgery.
As is known to those skilled in the art, modem surgical techniques typically employ radio frequency (RF) cautery to cut tissue and coagulate the same to stop bleeding encountered in performing surgical procedures. For historical perspective and details of such techniques, reference is made to U.S. Pat. No. 4,936,842.
As is known to those skilled in the medical arts, electrosurgery is widely used and offers many advantages including that of the use of a single surgical tool for both cutting and coagulation. A variety of proposals have heretofore been embodied in existing electrosurgical implements. Examples of such proposals include those set forth in U.S. Pat. No. 4,534,347 granted to Leonard S. Taylor Aug. 13, 1985, U.S. Pat. No. 4,674,498 granted to Peter Stasz Jun. 23, 1987, and U.S. Pat. No. 4,785,807 granted to G. Marsden Blanch on Nov. 22, 1988.
The first two of the foregoing patents illustrate implements having sharpened exposed edges (e.g., knife-blade like geometries) which are employed to perform conventional mechanical cutting of tissue. The last of the patents sets forth an unsharpened blade which has been entirely coated with an insulating layer so that cutting is performed by electrical energy capacitively transferred across the insulating layer rather than by conventional mechanical action. Thus, in electrosurgery, "cutting" is accomplished when energy transfer is sufficient to cause water in tissue cells to boil, thus rupturing the cell membranes by internal rather than external forces. High energy is required to effect such electrosurgical cutting. While the Blanch proposals have constituted an important advance in the art and have found wide-spread acceptance in the field of electrosurgery, there has been a continuing need for further improvement in electrosurgery to reduce thermal necrosis thereby decreasing post-operative complication, to reduce eschar production, to reduce incidence of heat damage to tissue away from the cutting site, and to increase the speed of cutting.